A terrorist chieftain in Pakistan masterminded the Mumbai massacre and kept in touch with the 10 attackers by satellite phone, Indian police believe.

They said Yusuf Muzammil, head of anti-Indian terror operations for the notorious Lashkar-e-Taibe, or LeT group, was identified by the only one of the 10 Mumbai attackers to survive, The Wall Street Journal reported.

His claim was backed up by a satellite phone left behind by the attackers in the fishing trawler they hijacked to reach Mumbai.

The phone’s records showed calls were made to Muzammil and four other LeT henchmen in the two days before the slaughter.

India is demanding that Pakistan hand over Muzammil and 19 others suspected of plotting the slaughter that killed 171 people in India’s financial capital last week.

But Pakistan has not responded to the demand, which threatens to escalate the powderkeg standoff.

Yesterday, Secretary of State Condoleezza Rice went to New Delhi to plead for calm. The Pentagon disclosed that Joint Chiefs of Staff Chairman Mike Mullen is making a rare visit to the South Asia region.

While Rice and other US diplomats are not publicly taking sides in the dispute between the two nuclear-armed rivals, a senior American official said yesterday there were “strong indications” that LeT was responsible for the carnage.

Pakistani Foreign Minister Shah Mehmood Qureshi also called for all involved to take a deep breath. “We want to defuse the situation,” he told reporters.”

But India’s government, under election-year pressure to take a harder line on terror, was further shaken when a bomb killed at least three people aboard a train in the country’s terrorist-hit northeast. There was no claim of responsibility.

Meanwhile, new details of the Mumbai attack emerged yesterday:

* Indian authorities said the attackers had taken steroids to build up their bodies during training – then took other drugs to stay awake during the three-day standoff with police and commandos.

“We found [syringes] containing traces of cocaine and LSD left behind by the terrorists and later found drugs in their blood,” one official told Britain’s Telegraph newspaper.

* Azam Amir Kasab, 21, the sole known terrorist to survive the attack, said his father introduced him to a LeT commander four years ago in return for a cash payment, the Times of London said.

Kasab also said he fears his family members will be killed because he failed his orders not to be taken alive.

* The attackers used sophisticated bomb triggers, called programmable electronic timer-delay devices, or PDTs, in at least two of the five bombs they set, the Mumbai Police Bomb Squad told ABC News.